Abstract The continued development of a rapid diagnostic method for testing the antibiotic susceptibility of urinary tract infections in near real-time is proposed. Currently, all methods for determining antibiotic susceptibility rely exclusively on detecting changes in the bacterial population caused by cell division after exposure to an antimicrobial compound. In our Phase I effort we demonstrated a novel phenotypic approach to antibiotic susceptibility testing that provides commensurate information without measurements of growth. Technical feasibility of this method was demonstrated by measuring the antibiotic susceptibility of both sensitive and resistant strains of Escherichia coli and Pseudomonas aeruginosa treated with antibiotics having different mechanisms of action. Susceptibility results were obtained within one hour time. In addition, resistant strains were easily distinguished from sensitive strains. Because grown cultures are no longer needed to obtain results, susceptibility results can be obtained directly from urinary specimens at the point of collection within 90 minutes total reducing the time from sample collection to availability by days enabling targeted therapy, improved patient outcomes, and the reduced spread and generation of resistant organisms. The method can be realized with a disposable device that is simple, cost effective, and ideal for mass production. The proposed Phase II effort focuses on extending our investigation to include all first and second line antibiotics used to treat uropathogens and developing a prototype test instrument. Project Narrative Urinary tract infections (UTIs) are among the most common of all bacterial infections, occurring primarily in women, and accounting for as many as 8 million outpatient visits to doctors annually. Furthermore, UTIs have become the leading healthcare-associated infection among adults and children in the United States. However, the management of UTIs has become more complicated over the last decade due to increasing antimicrobial resistance to first-line antibiotics. Already, authorities advise the use of significantly more expensive fluoroquinolones as a first line treatment for uncomplicated UTIs when the prevailing rate of antibiotic resistance in the area rises to greater than 20 percent. The same type of resistance of E. coli in other countries has reached a shocking 70 to 100 percent. Antibiotic resistance represents a problem of increasing societal importance brought about by the overuse or inappropriate use of broad-spectrum antibiotics. The proposed rapid test is an essential tool for the responsible and prudent use of prescribed antibiotics to prevent the spread of resistant bacterial strains.